true, but 400-800 volts is a particularly nasty voltage as there are just enough volts to drive a fatal current through the body due to its resistance..
most people who slip on something like a railway track are going to reach out with their hands to try and rebalance themselves – there is a very good chance they may touch the live rail with one hand and one of the earthed rails with the other, plus DC causes muscle contractions which can make the victim lock on to the live conductor (also causing secondary injury via burns)
I think one of the writers in Barking was killed this way a few years back..